1. Field of the Invention
The present invention relates to a return optical deflecting element, an optical deflecting element and optical scanners using the return optical deflecting element and the optical deflecting element.
2. Description of the Related Art
Optical scanning is utilized in a wide technical region of an optical printer, a bar code reader, etc. As is well known, an optical deflecting element for deflecting light in an optical scanning operation is generally constructed by various kinds of deflecting elements such as a rotary polygon mirror, a hologram disk, etc.
When a general return optical deflecting element is used, it is necessary to rotate a recording medium when information is read out of the recording medium and is written to be recording medium. Accordingly, it is impossible to simply write and read information out of the recording medium having a shape in which the recording medium cannot be easily rotated.
In a general optical scanner, it is impossible to solve problems about defocusing caused by field curvature in principle.
Further, it is impossible to greatly reduce a radius of gyration in the case of a general rotary polygon mirror as the optical deflecting element and perform the optical scanning operation at a high speed.